In the application of the peripheral devices of the computer system, the computer interface controller for the peripheral devices plays an important role. All kinds of the portable devices need to exchange data with the computer device through the computer communication interfaces, such as the USB interface, the PCMCIA interface, the CardBus interface, the SATA interface etc.
Currently the peripheral devices available in the market are designed to operate passively. That is, when a user uses the peripheral device in connection with a computer, the computer will provide an authorization level to the user according to the user name and authorization level registered in the operation system of the computer device and select the data transmission mode between the computer device and the peripheral device according to the given authorization level.
This information security policy, however, does not apply to the peripheral devices that are connected to the back end of the computer device. This is because the peripheral devices that are connected to the back end of the computer device are not able to determine the authorization level that the current user has registered in the operation system of the computer device. As a result, the computer device can not select the proper data transmission mode in connection with the peripheral device, according to the authorization level given to the user of the peripheral device.
It is thus necessary to provide a technology to enable the peripheral device to select the proper data transmission mode from time to time according to the authorization level given to the user of the peripheral device, as is registered in the operation system of the computer device. With such a technology, the security of the computer system will be further enhanced.